| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.18 118/150] tipc: fix unsafe rcu locking when accessing publication list | Date | Fri, 2 Nov 2018 19:34:40 +0100 |
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4.18-stable review patch. If anyone has any objections, please let me know.
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From: Tung Nguyen <tung.q.nguyen@dektech.com.au>
[ Upstream commit d3092b2efca1cd1d492d0b08499a2066c5ca8cec ]
The binding table's 'cluster_scope' list is rcu protected to handle races between threads changing the list and those traversing the list at the same moment. We have now found that the function named_distribute() uses the regular list_for_each() macro to traverse the said list. Likewise, the function tipc_named_withdraw() is removing items from the same list using the regular list_del() call. When these two functions execute in parallel we see occasional crashes.
This commit fixes this by adding the missing _rcu() suffixes.
Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/tipc/name_distr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/net/tipc/name_distr.c +++ b/net/tipc/name_distr.c @@ -115,7 +115,7 @@ struct sk_buff *tipc_named_withdraw(stru struct sk_buff *buf; struct distr_item *item; - list_del(&publ->binding_node); + list_del_rcu(&publ->binding_node); if (publ->scope == TIPC_NODE_SCOPE) return NULL; @@ -147,7 +147,7 @@ static void named_distribute(struct net ITEM_SIZE) * ITEM_SIZE; u32 msg_rem = msg_dsz; - list_for_each_entry(publ, pls, binding_node) { + list_for_each_entry_rcu(publ, pls, binding_node) { /* Prepare next buffer: */ if (!skb) { skb = named_prepare_buf(net, PUBLICATION, msg_rem,
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